


[Collection] Body Modification/Breeding Smut

by Night-Mare (Aoife)



Category: Katekyou Hitman Reborn!
Genre: Alternate Universe - Canon Divergence, Body Modification, Breeding Kink, M/M, Porn What Plot
Language: English
Status: In-Progress
Published: 2019-12-18
Updated: 2019-12-18
Packaged: 2021-02-26 01:21:20
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,625
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21852847
Author URL: https://archiveofourown.org/users/Aoife/pseuds/Night-Mare
Summary: What it says on the tin. Pairings in Chapter titles.
Relationships: Dino/Sawada Tsunayoshi
Comments: 3
Kudos: 136





	[Collection] Body Modification/Breeding Smut

He scrabbles at Dino’s shoulders, fingernails breaking his big brother’s skin in an ineffectual bid to find purchase as his cock finally pushes inside his body. Even with the meticulous preparation the stretch hovers on the edge of agonising, but it feels so good he can’t bring himself to make Dino slow down or withdraw. “Shhh, sweetheart. You’re being so good for me. That’s half of it you’ve taken; take a deep breath for me and then let it out as I slide the rest inside; remember what I said about you needing to make space?” He nods, breathless, muscles stretched well beyond what they should be capable of, and takes the ordered deep breath, letting it hiss out as Dino pulls his hips sharply towards him. 

His body protests the movement and he pants as something non vital gives way to make space for the obscene cock seeking to make its new home inside him. Dino’s hips come to rest against his ass and he tries to sigh in relief only to find that Romario and Bono hadn’t been wrong about how challenging he’d find it to breathe with his big brother’s cock inside him. But it does feel amazing, too, and he doesn’t regret his submission at all. 

“Let me breed you, sweetheart? You’ll look so pretty with my foals in your belly.” He nods. Dino grins, Flames radiant and starts to move and he concentrated on trying to remember how to breathe - and how not to freak out at the touch of cool air to sensitive flesh as his body clings relentlessly to Dino’s clock, unwilling to give it up. 

He should freak out at the sensation, but Dino strokes the smooth exposed flesh, petting it and praising him for being so in love with his cock that his body won’t let it go, then eases it off his cock, before stroking back inside, and he discovers an unexpected bonus to what should be terrifying; the adrenaline sharpens the sensations, and more of his gut is stretched around Dino’s long cock. 

“So good for me, otouto, letting me make space for my foals inside your tiny body. You’ll take such good care of them, won’t you, like Hayato’s going to have Bono’s kittens for him, and Takeshi’s going to give Romario a whole pack of puppies?” He nods again, and Dino withdraws again, unravelling more of his body with his cock, and it shouldn’t be hot to feel his big brother’s hand squeeze bits of his body that have no right to be on the outside. “Mmm. I’m half tempted to just stroke myself with this -“ he squeezes the thin sheath still covering his cock despite having pulled all the way out, “- otouto. It’s so tight and silky around my cock, and it would be so easy to use it just like a fleshlight -“ Dino demonstrates, and he keens as more and more of his body is pulled out and stretched to cover his nii-san’s cock. “- but on the other hand, if I do this -“ he makes a high pitched sound of relief as Dino forces himself back inside his hole, along with most of what he’s used to sheathe himself, applying even more pressure to his prostate. “- you warm it beautifully, and I get to feel all your muscles quiver and spasm tight. It’s quite the dilemma -“

He whines, abdominals clenching and Dino’s hips twitch, forcing him to exhale as his diaphragm is shoved up out of the way. “Want you to fuck all of me, Dino-nii.” His big brother groans, and wraps a hand around the base of his cock, to stave his orgasm off. “Tell me how to make it good for you, Dino-nii? Do I need to try and be tight, or lax and loose so you can empty me out for your foals?” 

“Fuck, sweetheart. Your _mouth_. “ His big brother fingers his hole and he shivers, squeezing as best as he can, and shrieking as he moves, forcing cock and fingers inside; the fingers hook the folds inside him, dragging them back out again, and finally, finally, there’s no more - or rather there’s a point of resistance, and Dino makes no effort to push past. “There we go, sweetheart. Now let me have your Flames, -“ he relaxes his grip and Dino shapes them and rocks into his body, pushing into him and sinking into the root, shaping the Flames around his cock, and making him shriek as his body burns and conforms to what’s inside it. When his Flames cool again, seeping back out of his muscles, Dino can rock in and out of him smoothly, nothing resisting or being pulled out of place, and more nerves fire than he’d ever dreamed of. “- nearly done. Doesn’t that feel good to be able to take me so easily, sweetheart?” 

He nods, squeezing the new muscles around his big brother’s cock, relishing in the sensation, and pressing a hand to his abdomen, feeling the way that even while full, it dishes in, and whines. “Promised foals?”

“So I did.” Dino folds himself to press a kiss to the corner of his lips. “You sure, otouto? There’s no going back once they’ve sparked, and I’ve wanted this for so long there’s going to be more than one.” He nods, eagerly; he’d daydreamed about it for _years_, but thought it impossible until Hayato had accidentally conceived and told him about it sheepishly, clearly expecting a lecture rather than starry eyes. His big brother whines, and bucks, and he gasps, the air punched out of his lungs by the unexpected movement. “I’m going to roll us both over; I want to see you slide down my cock, sweetheart. I need to make sure you’re enjoying this. Sky Flames can be tricksy about conception. It’s why we’re always allowed love matches even if they’re socially inconvenient.”

He makes a small squeak that has his big brother laughing as Dino does just that, and he finds himself held upright by the thick cock that occupied a good third of his abdomen. 

“Fuck, you look so good like that, sweetheart. Just knowing you’ve got my whole cock in your tiny body is almost enough to make me cum. It’s such an obscene mental image, and the fact that you want my foals, too, and that you’ll keep letting me stick my cock in you even when you’re nine months gone -“ He whimpers, legs stretched wide, unable to get his knees under him, and Dino takes mercy on him, sliding up the bed slightly, and then lifting him a little and dropping him back down again, dragging another helplessly squeaked gasp from him as the head of his cock slams into his diaphragm. It shouldn’t feel good, but it does, and Dino grins, repeating the action, lifting him a little more each time until he’s barely retaining the head of his cock, and gravity makes him take the shaft with brutal speed. 

Dino’s Flames curl through his system again, coiling in his belly, heightening the pleasure from his big brother’s cock, and he pants, barely able to keep his breathing synchronised with the way he’s being used for their combined pleasure. He’s rolled back beneath his big brother as the Flames keep surging through his abdomen, curling and flaring and he can feel them rebuilding his body to make the pregnancy they both want possible. It’s as worryingly hot as the earlier sensation of being turned inside out to make space for his nii-san’s cock, and yet more nerves flare to life, copying those that made penetration pleasurable and spreading them throughout his abdomen.

The Flames draw back out of his abdomen again, and he presses one of his hands to his belly, feeling the way it’s still dished, but slightly less than it had been, and then shaping the new organ and his big brother’s cock. It makes Dino buck, the extra stimulation not helping his big brother’s composure. “Mmmm. Shall we fill you up now, sweetheart? With conception as motivation, my Flames will be in overdrive; you’re going to look so pretty with your new womb full of my seed.”

He nods, and Dino rocks into him, long, slow thrusts, grinding at the deepest point, stretching him and forcing the air from his lungs, stimulating the nerves there - new, a gift of the Flames they’d both poured into his abdomen - and stoking the low, rolling flames of his arousal into a raging bonfire that sends his muscles into spasming, clenching impossibly tight and milking the cock piercing him with impossible to resist ‘pulls’ that drag his brother’s orgasm from him. An orgasm that goes on and on and on, rolling over and through both of them, and he _feels_ the pulses of cum, rich with Flames that provoke his own to pool in the same space.

They _both_ feel the resulting sparks shimmer to life, and Dino eases his cock out of his body, and he has a moment of panic at the memory of his body unravelling the first time it had been pulled out, but the modification they’d created holds, and the absence only leaves him feeling painfully hollow and wobbly. They’d planned for that, though, and Dino manages to grab the plug from the bedside table, sliding it into his body, which grips it gratefully for all it’s smaller than his big brother’s cock. Once it’s in place, Dino curls around him, warm and safe, and drags a blanket over both of them. He finds it remarkably easy to sink into sleep, and Dino’s murmured, “- so good for me, sweetheart. I never thought you’d want this. Going to keep you safe and pregnant and happy for ever and ever and ever.”


End file.
